Proposal Information for 2002A-0254

Abstract: Perhaps the strongest phenomenological clue to the physical origin of radio sources is the recognition that the majority of radio galaxies can be classified, according to where most of the radio luminosity is radiated, into two morphological types: FRIs - or edge darkened, and FRIIs - or edge brightened (Fanaroff & Riley 1974). The FRI - FRII dichotomy is key in understanding the processes that lead to the onset of nuclear activity, the formation of radio jets, the time-evolution of radio lobes and the interaction of the radio structure with the surrounding medium. Until now, however, it has proven impossible to discriminate between competing scenarios, due to the lack of a critical piece of information: the mass \mh of the central black hole which is at the very core of the AGN paradigm. The recent discovery of a tight correlation between \mh and the large scale velocity dispersion \sigma of the host galaxy (Ferrarese & Merritt 2000), has put us in the unique position of being able to address this deficiency. We propose to obtain long-slit spectra with the R-C spectrograph for a sample of 19 FRI and FRII sources, selected for having optical high-resolution HST images. The combination of the KPNO data, archival HST images, and radio data already in hand will lead to a complete suite of dynamical, morphological, and nuclear information.